This invention relates to a system including a press and special tooling fitted to the press for forming can ends, particularly of the self-opening type. Typical such systems are disclosed in U.S. Pat. Nos. 4,599,884 and 4,637,961 which relate to making shells for can ends, and No. Re. 33,061 which relates to converting shells to can ends. Such presses and systems have been fitted with programmable controllers (PLCs) in the past, however operator interface has been minimal, generally in the form of lamps, gages, or a few messages on a small bill-board style display. The systems are complicated, use tooling of high precision, and operate at relatively high speed. There is a need for better monitoring of system operation to avoid damage to the tooling or the press if there is a fault which is not quickly detected. There is also a need to maintain a better history of press operation, to allow study of causes for down time, and to assist in analysis of subsystems performance and further develop maintenance procedures and schedules.
By way of one specific example, shell systems are now provided which include up to twenty-seven lanes of shell making tooling and operate at speeds in the order of 350 press revolutions per minute, for as much as twenty two hours/day. Any misfeed of parts can result in a jam within the tooling that in turn can severely damage the tooling, and the resultant down time of the system can represent great amounts of production loss. There is a need not only to detect and react quickly to malfunctions, but also to capture and observe information and data which may assist in predicting potential malfunctions within these systems. Even if there is not a damaging jam, various detectors are arranged to stop the press in anticipation of a malfunction, or in response to a malfunction of a peripheral device (e.g. a stock feeding or a product discharge apparatus). Frequent stops can lead to excessive wear in the main clutch of the press.
As mentioned previously, PLCs have been used to control such press machinery, but each type of installation requires a unique program for the PLC to couple it to the press and its various control and detection devices, e.g. the main clutch, the hydraulic motor, and detectors in both the moving press parts and in the special tooling fitted to the press. This programming functions as the control circuitry for running the press through it several regimens.
Various forms of interface and monitoring systems, which may interface with PLCs for controlling complicated manufacturing machinery, are per se known. These systems include CRT monitors, lights and gage displays, and keyboards or other input/output consoles for use by an operator in starting, stopping, and controlling such machinery. However, none have heretofore been applied to can end systems.